Distance-adjusting mechanism for bellows camera

Abstract

A bellows camera has a housing movably connected with its lens mount by a scissor linkage including two pairs of intersecting arms on opposite sides of the lens mount, a first arm of each pair having one end pivoted to the housing and the opposite end guided in a slot on the lens mount whereas a second arm of each pair has one end pivoted to the lens mount and the opposite end guided in a slot on the housing. The slot-guided ends of the two second arms are engaged by respective rack members, slidable at right angles to the optical axis, which are in mesh with a pair of pinions on a common shaft traversing the housing and carrying a setting knob. If the knob is rotated beyond a limiting position of an operating range, corresponding to focusing on infinity, the rack members are cammed out of engagement with their respective scissor arms to enable manual collapsing of the camera.

I claim: 
     
       1. A camera comprising: a housing adapted to receive a photographic film to be exposed;   a lens mount provided with an objective centered on an optical axis, said lens mount being receivable in said housing in a collapsed position and being axially sparable therefrom for movement into a picture-taking position;   a bellows forming a lighttight enclosure between said lens mount and said housing;   an articulated linkage connecting said lens mount with said housing, said linkage being divided into two symmetrical sections on opposite sides of said axis; and   a focusing mechanism on said housing coacting with both said sections for varying the axial separation of said lens mount from said housing, said mechanism including a shaft skew to said axis traversing said housing in a plane perpendicular to said axis, an actuator on said shaft, a pair of pinions secured to said shaft at opposite extremities thereof, and a pair of parallel rack members respectively in mesh with said pinions and movable parallel to said plane.   
     
     
       2. A camera as defined in claim 1 wherein said sections comprise a pair of scissor links each including a first arm with one end pivoted to said housing and a second arm with one end pivoted to said lens mount, said first arm having its other end guided in a slot on said lens mount, said second arm having its other end guided in a slot on said housing, each of said rack members having a coupling formation engageable with a coacting formation on said other end of said second arm of the respective scissor link. 
     
     
       3. A camera as defined in claim 2 wherein each of said rack members is laterally swingable about a point of contact with the respective pinion to disengage said coupling formation from said coacting formation, further comprising deflecting means on said housing for laterally swinging each rack member upon movement thereof past a limiting operating position, thereby decoupling said actuator from said scissor links and facilitating a collapsing of said linkage. 
     
     
       4. A camera as defined in claim 3 wherein said rack members are provided with respective biasing springs tending to keep said coupling and coacting formations engaged, each of said biasing springs having a first leg which bears upon the respective rack member in the vicinity of said point of contact and a second leg which bears upon the respective rack member in the vicinity of said coupling formation. 
     
     
       5. A camera as defined in claim 4, further comprising bearing means forming a pair of wedge-shaped lodgments around said shaft in proximity to said pinions, said lodgments pointing away from said pinions, disengagement of said coupling and coacting formations by said deflecting means stressing said second leg to intensify the biasing force exerted by said first leg through the respective rack member and pinion upon said shaft for wedging same more firmly into said lodgments to prevent spontaneous rotation of said shaft. 
     
     
       6. A camera as defined in claim 3 wherein said deflecting means comprises a pair of studs on said housing engageable in said limiting operating position with a pair of camming surfaces on the respective rack members, said coacting formation being a pin, said coupling formation being a long prong and a short prong separated by a gap for bracketing said pin in an engaged position, said long prong being located between said gap and said point of contact for intercepting said pin upon re-extension of the collapsed linkage. 
     
     
       7. A camera as defined in claim 6 wherein said short prong has a flank averted from said long pin constituting the respective camming surface, thereby facilitating re-entry of said pin into said gap upon re-extension of said linkage. 
     
     
       8. A camera as defined in claim 3 wherein said mechanism includes indexing means for yieldably arresting said actuator in said limiting operating position and stop means for preventing a movement of said actuator beyond an opposite extreme position.